MCAS - Worksheets
Name __________________________________ Date ______________________ Section _________
Chapter 2 - Living Systems: Ecosystems
Lie Science Standards: 12, 13, 14, 15, 17
1. A species of bird migrates from South
America across the Atlantic Ocean to its
summer breeding ground in northern Canada.
The birds stop on the east coast of the United
States to eat the eggs of horseshoe crabs. The
migration route of these birds is shown on the
map below.
4. The heath hen, an extinct small wild fowl,
was a relative of the prairie chicken. Which of
the following most likely caused extinction of
the heath hen?
A. overhunting
B. stable climate
C. plentiful food supply
D. abundant nesting sites
5. Lichens are symbiotic organisms made of
green algae and fungi. What do the green algae
supply to the fungi in this symbiotic
relationship?
A. carbon dioxide
B. food
C. protection
D. water
Which of the following changes would most
threaten this species of bird with extinction?
A. less rainfall in South America
B. longer summers in North America
C. increased sizes of horseshoe crab eggs
D. decreased populations of horseshoe crabs
2. Some types of bacteria can only live where
oxygen is not present. These bacteria were well
adapted to life on Earth over 2 billion years ago.
Which of the following changes caused many of
these bacteria to become extinct?
A. the slow movement of tectonic plates
B. the varying temperatures of each season
C. an increase in volcanic activity under the
oceans
D. an increase in the number of photosynthetic
organisms
3. Which of the following organisms produces
energy from sunlight?
A. worm
B. rabbit
C. hawk
D. grass
6. The praying mantis is a predatory insect that
often eats moths. The graph below shows the
relative numbers of two species of moths over
12 weeks after the introduction of the predatory
praying mantis.
What characteristic of this ecosystem is best
indicated from this graph?
A. Species B was preferred as food over
species A.
B. Species B may replace species A in this
environment.
C. Species B will reproduce more rapidly than
species A.
D. Species B was more abundant at the
beginning of this time period than species A.
7. Which of the following symbiotic
relationships is considered parasitic?
A. ticks feeding on a dog
B. bees transporting pollen from flowers
C. pilotfish swimming under sharks
D. birds eating the insects from the back of a
hippopotamus
8. Most of the bacteria in a forest ecosystem are
best classified as which of the following types
of organisms?
A. consumers
B. decomposers
C. predators
D. producers
9. A rabbit population has increased noticeably
in the past ten years. Which of the following is a
reasonable hypothesis for this population
growth?
A. Competition for food has increased among
rabbits.
B. The rabbit’s main predator has been
eliminated by human development.
C. Abnormal weather conditions have
decreased water levels of the local ponds.
D. An organism that relies on similar food
sources has migrated into the area.
10. The diagram below shows a partial food
web for some of the organisms in an area.
11. The diagram below shows a food web.
If the corn and oats were completely removed
from the above food web, which of the
following would be the most affected?
A. mice and rats
B. hawks and owls
C. snakes and raccoons
D. grasshoppers and crickets
12. Wolves kill many elk every year and often
attack old, sick, and injured members of a herd.
Which of the following best describes the role
of the wolves in the wolf-elk relationship?
A. competitor
B. host
C. parasite
D. predator
13. The population of which of the following
organisms would most likely decline if small
animals like rats, rabbits, and snakes were
eliminated from an ecosystem?
A. earthworms
B. grasses
C. hawks
D. mushrooms
If all the trees in the area were cut down, the
energy supply of which population would be
most directly affected?
A. aphid
B. grasshopper
C. oriole
D. rabbit
14. How does a mushroom obtain energy?
A. by attaching to green plants and taking the
plants’ food
B. by combining carbon dioxide and water to
make its own food
C. by absorbing matter from dead organisms to
use as food
D. by attacking bacteria and using the bacteria
as food
15. The diagram below represents a cycle in an
ecosystem.
Which of the following do the arrows most
likely represent?
A. heat
B. nutrients
C. sunlight
D. water
16. The complete removal of decomposers from
an ecosystem will have the greatest effect on
which of the following?
A. the spread of disease
B. the availability of water
C. the recycling of nutrients
D. the distribution of organisms
17. Which of the following best describes a role
of mushrooms in ecosystems?
A. capturing energy from sunlight
B. consuming living plant material
C. taking energy from animal hosts
D. breaking down dead plant material
20. Which of the following groups of
organisms uses sunlight to convert carbon
dioxide and water into sugar and oxygen?
A. carnivores
B. decomposers
C. herbivores
D. producers
21. Human activity most likely contributes to
which of the following changes on Earth?
A. an increase in the length of a day
B. a decrease in the number of volcanic
eruptions
C. a decrease in the magnitude of large
earthquakes
D. an increase in the amount of atmospheric
carbon dioxide
22. Fossilized coral reefs, fish, and other warm
water marine creatures have been found in
mountainous regions of New England. Which of
the following best explains how this could have
occurred?
A. The climate and geology of this area have
changed over time.
B. These creatures were better adapted to cold
climates at one time.
C. The process of fossilization greatly changed
the original material.
D. Scavengers carried the remains of these
creatures to higher regions.
23. The diagram below shows an energy
pyramid for a lake ecosystem.
18. Which of the following has changed over
the last 200 years primarily due to human
activity?
A. Earth’s magnetic field
B. the frequency of earthquakes
C. Earth’s tectonic plate activity
D. the composition of the atmosphere
19. Which of the following is most responsible
for the decay of dead organisms?
A. water
B. mammals
C. microorganisms
D. nitrogen
Which of the following best describes the role
of the perch in this energy pyramid?
A. producer
B. decomposer
C. primary consumer
D. secondary consumer
24. In an effort to preserve wildlife on his farm
in Massachusetts, a farmer decides to stop using
a 10-acre field. The farmer fences off the area,
stops cutting the grass, and stops allowing
livestock to graze on it. After twenty years, the
area would most likely
A. be covered with moss and rocks.
B. be a mature hardwood forest.
C. be grown over with bushes and small trees.
D. be barren due to lack of maintenance.
25. Lightning from a thunderstorm strikes a tree
that falls to the forest floor and dies. During the
next few years the dead tree undergoes many
changes. What organisms are most likely
responsible for the biological and chemical
changes to the tree?
A. consumers
B. decomposers
C. predators
D. producers
26. A forest ecosystem in New Hampshire contains a large area where berry plants grow naturally. The
berry plants help some organisms in the forest survive and grow. Other organisms in the forest help the
berry plants survive and grow.
a. Describe two different ways that the berry plants help some organisms in the forest survive and
grow.
b. Describe two different ways that other organisms in the forest help the berry plants survive and
grow.
27. Dead plant and animal matter are broken down by different organisms. This decay process benefits
other organisms in the ecosystem.
a. Name two different organisms that help break down dead plant and animal matter.
b. Describe how living plants benefit from the breakdown of dead plant and animal matter.
c. Explain what would most likely happen to an ecosystem if all the organisms that break down
dead plant and animal matter suddenly disappeared.
28. The partial food web below shows five different organisms that are found in a prairie ecosystem.
a. Identify each organism in this food web
as a producer, a primary consumer, or a
secondary consumer.
b. Using only the organisms from this food
web, describe one change in this prairie ecosystem that would result in a decrease in the grasshopper
population. Explain the reasoning for your answer.
29. The organisms in an ecosystem interact in many ways to survive. For example, a rosebush, aphids,
beetles, spiders, and orioles all interact in a rosebush ecosystem. The diagram below shows how these
organisms interact in a partial food web.
a. Identify the producer organism
in this food web. Explain the
reasoning for your answer.
b. Identify the primary consumer
organism in this food web. Explain
the reasoning for your answer.
c. Describe what would most likely happen to each of the other organisms in the food web if the beetle
population were suddenly destroyed. Explain the reasoning for your answer for each organism.
30. The diagram below shows a food web.
Members of this forest community get materials they need to survive from the ecosystem. These
materials are constantly being recycled.
a. Explain the role of grass in this food web, and include in your response why it is at the bottom of
the web.
b. What is the role of the grasshopper in this food web?
c. Explain what would happen to the population of snakes if the rabbits were suddenly removed
from this ecosystem.
d. Explain what would happen to the grasshopper population if the insect-eating birds were
suddenly removed from this ecosystem.